A purpose-designed BOP handling system comprising twin air-operated monorail hoists, with a joint lifting capacity of 200 tonnes has been supplied by J D Neuhaus. These hoists are a special compact design which has been developed to suit on-site operational requirements and each hoist represents a 45% reduction in the horizontal profile length compared to the JDN standard EH-100 product.
These compact hoists run in parallel on two overhead beams in excess of 22 metres in length. Both hoists incorporate two trolleys, each with a 50 tonne load rating, providing a total 100 tonne lift capacity per hoist. Each hoist is also fitted with a copper-coated bottom block and clevis (providing increased spark protection), together with a galvanised chain box. The overhead support beams incorporate a rack and pinion drive for the trolleys, ensuring that even inclines up to 2.5° can be negotiated. The total traverse distance is in excess of 18 metres, while the lift height available is 15.25 metres.
A single Neuhaus LN trolley with a 50 tonne load capacity has also been incorporated which is used to provide a BOP fixture device during maintenance works.
Both hoists incorporate overload protection, with limit switches also provided for the hoist and traverse operations. The hoist motors are also fitted with an additional ‘emergency’ manual brake release handle located on the motor cover. Hoist operation and traverse movements are achieved with a pendant controller having an 8 metre attachment hose and incorporating an additional interface for an extra local control box. A central control box with 23 metres of control line ensures that both hoists can be controlled from one location. The hoists are operated from a 6 bar air supply, with 2 main air supply chain systems provided to accommodate both the 22 metre support beam travel lengths plus the 18 metre hoist movements.
Air service units comprising filter, regulator and oiler are hoist mounted, and the equipment has full JDN offshore kit and 4-coat epoxy paint finish, together with full testing and certification for Ex-classification: Ex II 2 GD IIB T4.
[mappress] Subsea World News Staff, May 16, 2012; Image: J D Neuhaus